map 插入数据的方式局别

#include<map>
#include<iostream>

usingnamespace std;

int main()
{
map <int, int> m1, m2, m3;
map <int,int>::iterator m1_Iter;

m1.insert( pair <int, int>(1, 10 ) );
m1.insert ( pair <int,int> ( 2, 20 ) );
m1.insert ( pair <int,int> ( 3, 30 ) );
m2.insert ( pair <int,int> ( 10, 100 ) );
m2.insert ( pair <int,int> ( 20, 200 ) );
m3.insert ( pair <int,int> ( 30, 300 ) );

cout << "The original map m1is:";
for ( m1_Iter = m1.begin( ) ; m1_Iter != m1.end() ; m1_Iter++ )
cout << " "<<m1_Iter->second;
cout << "."<< endl;
return 0；
}

　　map

   

m1.insert( pair <string, int>("str", 10 ) );
m1.insert( pair <string, int>("str1", 11 ) );
m1.insert( pair <string, int>("str", 12 ) );

不会插入键相同的值，也就是不会覆盖

m1["sa"]=2;
m1["sa1"]=10;

这种方式就可以覆盖键对应的值